callivert - 4:41 am on Sep 28, 2007 (gmt 0)

I'm thinking to buy such a domain in a country extension and not sure which one to pursue.

Start again.
They're yesterday. They're not that catchy anymore. If you're ipod or esurance or whatever, that prefix helped get you there, but now it's just part of your brand name- the curve of the coke bottle as it were. :-)
No new business should begin with these in 2007.
e stands for "electronic" as in "email", and "i" stands for internet. As people get more used to internet technology, the idea of branding yourself as being online has less sparkle.
Why do you want these prefixes?
Both domains are taken (I assume from your wish to "pursue" them).
Have you brainstormed? How many other branding ideas did you have? Write a list of thirty new ideas, and go from there.
I guarantee you, you'll think of at least three golden branding ideas that are not taken.